1. Field of the Invention
The present invention relates to the field of portable electronic devices that contain display devices. More particularly, the present invention relates to flexible display devices than can be folded and that can display information on both sides.
2. Related Art
Digital display devices are found in numerous electronic products such as wrist watches, hand calculators, cell phones and Personal Digital Assistants (PDA). Flat panel displays are included in certain applications both to present information to the user as well as to accept input data by means of user touch screen commands. Such displays can be used to present information as well as to accept touch screen commands from a digitizer located on the display.
Digital displays of various dimensions are available to accommodate a multitude of different applications according to the required viewing area. The viewing area for a wrist watch display would likely be too small for either a cell phone or a PDA. Likewise, the viewing area desired for a PDA would probably be too large for the form factor of either a wrist watch or a cell phone. Furthermore, a dual sided display might be called for in the case of a PDA, whereas a wrist watch would probably not require a dual sided display.
In some instances, it would be advantageous to incorporate at least two different applications in a single unit with a single display screen. For example, a digital clock function might be included in a digital calculator having a single digital display. On the other hand, including a calculator function in a digital wrist watch might require a slightly larger single digital display. Similarly, a cell phone function could be incorporated with a PDA function in a single unit having a single digital display. Clearly this would be a very desirable combination.
The problem created here is related to the viewable area of the display screen. The physical dimensions of a typical cell phone, described as the candy bar form factor, are considerably smaller than the physical dimensions of a PDA, described as the PDA form factor. In order to make use of a single display, the larger PDA form factor must be used. Using a device having the dimensions of a PDA as a cell phone would be both cumbersome and awkward.
One attempt to resolve this problem has been the use of a single, dual sided digital display having the candy bar form factor of a cell phone. Using the entire area of one side of the display for the PDA function, the width of the display area is a number of times greater than the height of the display area. A reduced portion of the reverse side of the display is then used for the cell phone function. One difficulty of this design is that the PDA display area is restricted to the physical dimensions of the cell phone.
In an effort to increase the display area of the PDA function, the use of two separate but equal area digital displays placed side by side in a foldable support mechanism has recently been proposed. In the unfolded position, the two separate side by side displays have a PDA form factor. In the folded position, the two separate displays are back to back and have a candy bar form factor that is about one half the PDA form factor. The problem here is the segmented appearance or page like separation of the side by side displays in the unfolded position. Furthermore, the cost and complexity of using two digital display units is prohibitive.
Accordingly, the present invention provides a mechanism for coupling a foldable, dual sided display device to a non-rigid support mechanism that will allow folding of the display device without any loss of useable area due to the folding operation. More specifically, the non-rigid support mechanism is used to provide a bend radius during folding of the display device such that a page like separation along the fold axis of the display device is eliminated. Further, the non-rigid support mechanism holds the usable area of the display device in a flat plane in both the folded and the unfolded positions. In the unfolded position, the display device has a Personal Digital Assistant (PDA) form factor. In the folded position, the display device has a candy bar form factor which is about one half the PDA form factor which is useful in cell phone applications. The display device can be double sided and one side of the display device is used in the folded position and the other side of the display device is used in the unfolded position. It is appreciated that in one embodiment both sides of the display device can be used to present information as well as to accept touch screen commands.
A foldable display device coupled to a non-rigid support mechanism movable between an unfolded and a folded position is described. The e-ink display device is dual sided and both sides can display information as well as accept touch screen commands in one embodiment. One side of the display device is used in the unfolded position and the opposite side is used in the folded position. In the unfolded position, the display device has a Personal Digital Assistant (PDA) form factor, and the entire area of one side of the display device is viewable.
The display device is supported within the non-rigid support mechanism such that it lies in a flat plane in the unfolded position, and there is no loss of viewable area due to folding of the display device. The two sides of the non-rigid support mechanism are coupled for movement between a folded and an unfolded position and the display device is folded in a bend radius that precludes any disruption to the display area. Moving the support mechanism from the unfolded position to the folded position folds the display device about an axis that divides the display device into two equal rectangles. In the folded position, the display device has a candy bar form factor useful in cell phone applications, and the viewable area is about one half that of the PDA form factor used in the unfolded position. The non-rigid support mechanism holds the viewable area of the display device in a flat plane in the folded position.
More specifically, an embodiment of the present invention includes a non-rigid support structure having a hinge mechanism that allows folding the structure between an unfolded position and a folded position. A dual sided, flexible display device is coupled to the support mechanism such that the display device is fully functional in both the folded and the unfolded positions. Coupling of the display device to the support mechanism is such that the display device is folded along an axis that divides the display device into two equal area rectangles. The hinge mechanism is designed to fold the display device with a bend radius along the fold that eliminates any crease, fold or bend of the display device. The support structure is designed to hold the viewable area of the display device in a flat plane in both the folded and the unfolded positions. In the folded position, the display device will have a candy bar form factor useful in cell phone applications, which is about one half the Personal Digital Assistant (PDA) form factor in the unfolded position.
A second embodiment of the present invention provides a mechanism for coupling a dual sided, flexible display device and a hinged support mechanism such that moving the hinged support mechanism from an unfolded position to a folded position will result in folding the flexible display in half. The flexible display is coupled along the length of the hinge mechanism. The hinge mechanism is designed such that the bend radius of the display device is great enough to prevent any crease, fold or bend of the viewing area of the display device. In the folded position, the display device will have a candy bar form factor useful in cell phone applications, which is about one half the Personal Digital Assistant (PDA) form factor in the unfolded position.
A third embodiment of the present invention provides a mechanism for coupling a dual sided, flexible display device and a non-rigid support structure having a folded position and an unfolded position wherein the viewable area of the flexible display in the unfolded position is about twice the viewable area in the folded position. The non-rigid support structure utilizes a flexible folding structure rather than a hinge to provide the means for moving the non-rigid support structure between the folded and the unfolded positions. The flexible folding structure provides the means for folding the flexible display with a bend radius that eliminates any crease, fold or bend of the entire viewable area of the flexible display. In the folded position, the display device will have a candy bar form factor useful in cell phone applications, which is about one half the Personal Digital Assistant (PDA) form factor in the unfolded position.